Nyquist-Shannon Theorem

The Nyquist-Shannon Theorem states that any complex signal, like audio or images, can be perfectly reconstructed if it is sampled (measured) at a rate at least twice its highest frequency component. This means that to accurately capture and reproduce the original signal without losing information, you must sample it fast enough—specifically, more than twice the maximum frequency present. If you sample too slowly, the reconstructed signal will have errors or distortion, known as aliasing. In essence, the theorem defines the minimum sampling rate needed to accurately translate a continuous signal into digital form and back.